local headers = ngx.req.get_headers()
ngx.say("Host:", headers["Host"], "<br/>")
ngx.say("user-agent:", headers["user-agent"], "<br/>")
ngx.say("user-agent:", headers.user_agent, "<br/>")
for k, v in pairs(headers) do
    if type(v) == "table" then
        ngx.say(k, ": ", table.concat(v, ","), "<br/>")
    else
        ngx.say(k, ": ", v, "<br/>")
    end
end

